phased.TwoRayChannel problem

Question

Wei-Min Chen 2019-1-4

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链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/438221-phased-tworaychannel-problem

回答： Kaushik Vasanth 2019-3-15

I'm setting a radar simulation platform.

Since the multipath effect is considered, I use phased.TwoRayChannel instead of phased.FreeSpace

The size of xr, Radar Data Cube, is (1100,10,64) which means fast time samples, ULA sensors and number of sweeps respectively.

% Radar Data Cube (Time Domain Received Signal)
xr = complex(zeros(waveform.SampleRate*waveform.SweepTime,Num_of_channel,Nsweep));
    for m = 1:Nsweep
        % Update radar and target positions
        [radar_pos,radar_vel] = radarmotion(waveform.SweepTime);
        [tgt_pos,tgt_vel] = carmotion(waveform.SweepTime);
        % Transmit FMCW waveform
        sig = waveform();
        txsig = transmitter(sig);
        % Radiate the pulse toward the target
        txsig = radiator(txsig,tgtang);
        % Propagate the signal and reflect off the target
        txsig = txchannel(txsig,radar_pos,tgt_pos,radar_vel,tgt_vel);
        rxsig = cartarget(txsig);
        rxsig = rxchannel(rxsig,radar_pos,tgt_pos,radar_vel,tgt_vel);
        % Collect the echo from the incident angle at the antenna
        rxsig = collector(rxsig,tgtang);
        % Dechirp the received radar return
        rxsig = receiver(rxsig);
        dechirpsig = dechirp(rxsig,sig);
        % Visualize the spectrum
        % specanalyzer([txsig dechirpsig]);
        xr(:,:,m) = dechirpsig;
    end

The results I got is:

I have no idea why the results are correct only if I use phased.FreeSpace.

I guess the collector is the point.

Thank you for all your assistance !

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Honglei Chen 2019-1-4

Is there a questino about the two ray channel? thanks.

Wei-Min Chen 2019-1-4

编辑：Wei-Min Chen 2019-1-4

Sure, if I replace phased.TwoRayChannel with phased.FreeSpace, the simulation results are correct.

So I assumed that the point is phased.TwoRayChannel. (Or Collector, I mean maybe I shouldn't use phased.TwoRayChannel with ULA+Collect at the same time.)

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Answer 1

Kaushik Vasanth 2019-3-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/438221-phased-tworaychannel-problem#answer_365547

Hi,

Maybe this could give an idea.

This example in mathworks shows the two-ray propagation. "https://in.mathworks.com/examples/phased-array/mw/phased-ex90572992-radar-signal-simulation-and-processing-for-automated-driving?s_tid=srchtitle".

Here when you change from phased.FreeSpace to phased.TwoRayChannel, we need to model 2 different channels for Tx and Rx.

Just have a look through the code and it might be of some help.

Thanks!